Best practice drill & blast: Blast design and implementation

Tying in a blast hole

Best practice mining means making sure ore and waste can be mined separately and without losing any ore.

To achieve this outcome, the geologist must be able to accurately calculate the direction and the distance of the rock movement following a blast – the movement must be both predictable and consistent to allow the position of the ore block to be adjusted to compensate for the movement.

How can this be achieved?

Blast optimisation begins with good blast design. A good design – if implemented accurately – will not only achieve the desired fragmentation but will also minimise dilution and reduce costs for both the drill and blast, and downstream processing operations.

Select the initiation system based on best-for-project

Two big factors in a blast’s design that impact how rock movement is controlled on an individual blast basis are detonation timing and the location of the blast initiation point. The timing between rows and holes has the most influence over the movement, both horizontally and vertically.  Each type of initiation system has varying degrees of capability when it comes to delivering accurate timing so the system should be selected on a best-for-project basis.

Execute the design to exacting standards

To predict blast-induced movement, and achieve optimal fragmentation, blast designs must be implemented exactly as designed. Quality, accuracy and consistency must be attained in all processes from design through to pattern mark out, collar position, drilled hole depth, inclination of holes, correct charge, stemming lengths and tie-in.

Facilitating continuous improvement

Being able to review results from a blast, knowing that everything was as per the design, allows the blast engineer to target any changes that need to be made to further optimise the next blast. The engineer can make a single change with confidence that it was the only parameter different from the previous blast.

Best practice drill & blast: Blast design and implementation was last modified: May 8th, 2019 by brandonegroup